Sulphur Hexafluoride and regulatory changes
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Better management or replacement?
Recent changes in regulations in North America may have an effect on how you think about SF6
SF6 and its background
SF6 refers to sulphur hexafluoride, which is a colourless, odourless, non-toxic, and non-flammable gas. It belongs to a group of synthetic gases known as fluorinated greenhouse gases (F-gases).
Postage stamp of Henri Moissan, France 1986
Sulphur hexafluoride (SF6) was discovered by French chemists Henri Moissan and Paul Lebeau in 1901. They synthesized SF6 by reacting sulphur with fluorine gas. SF6 has excellent electrical insulating and arc-quenching properties, making it widely used in electrical transmission and distribution equipment such as circuit breakers, switchgear, and transformers.
SF6 is commonly used as an electrical insulator in high-voltage applications due to its high dielectric strength. It effectively prevents electrical discharges and arcing, which helps maintain the integrity and safety of electrical equipment. Its high density also allows for compact designs of electrical devices.
Additionally, SF6 is known for its exceptional thermal conductivity and chemical stability, which further contribute to its suitability in high-voltage applications. It remains stable and does not decompose under normal operating conditions, ensuring long-term performance and reliability of electrical equipment.
GHG, GWP and SF6
A greenhouse gas (GHG) refers to any gas in the Earth's atmosphere that can trap heat and contribute to the greenhouse effect. These gases absorb and emit infrared radiation, which leads to an increase in the Earth's surface temperature. The greenhouse effect is a natural process that helps maintain the Earth's temperature at a habitable level. However, human activities have significantly increased the concentration of GHGs in the atmosphere, leading to enhanced warming and climate change.
The global warming potential (GWP) is a measure of how much a gas contributes to global warming over a specific time period, usually 100 years, relative to carbon dioxide (CO2).
CO2 has a GWP of 1 by definition.
SF6 has a GWP of 23,500, which means that it has a warming effect 23,500 times greater than that of CO2 over a 100-year period. This high GWP is primarily due to the long atmospheric lifetime of SF6, which can persist in the atmosphere for centuries before being removed.
Dangers of using SF6
While SF6 is widely used in electrical applications due to its favourable properties, it does pose certain dangers and environmental concerns:
SF6 sulfur hexafluoride CAS 2551-62-4 chemical substance in white plastic laboratory packaging
Environmental Impact: SF6 is a potent greenhouse gas with a high global warming potential (GWP). Its long atmospheric lifetime (about 3,200 years) contributes to its persistence in the atmosphere and its ability to trap heat. The high GWP of SF6 makes it a significant contributor to climate change.
Health Hazards: SF6 is non-toxic, but when released into the atmosphere in high concentrations, it can displace oxygen and pose asphyxiation risks in confined spaces. Additionally, if SF6 comes into contact with high-energy sources such as electrical arcs, it can produce toxic byproducts.
Leakage and Emissions: SF6 gas can leak from electrical equipment during installation, operation, or maintenance, leading to emissions. These emissions contribute to the overall greenhouse gas inventory and are subject to regulations and reporting requirements in many jurisdictions.
Cost and Energy Intensity: SF6-based electrical equipment requires specialized handling, monitoring, and maintenance, which can incur additional costs. The energy-intensive production process of SF6 also contributes to its environmental footprint.
Substitution Challenges: Transitioning away from SF6 in certain applications poses technical challenges due to its unique electrical properties. Identifying suitable alternatives and ensuring their compatibility and safety can be complex.
The Regulatory changes
To mitigate the dangers associated with SF6, efforts are underway to minimize its usage, improve containment and leak prevention measures, promote recycling and proper disposal, and develop alternative insulation technologies with lower environmental impacts. Governments, industries, and research organizations are actively working towards reducing SF6 emissions and transitioning to more sustainable solutions to address its environmental and health concerns.
The California Air Resources Board’s (CARB) regulation for Reducing Sulfur Hexafluoride Emissions from Gas Insulated Switchgear took effect in 2011 and is codified in the same subchapter as CARB’s mandatory GHG reporting and cap-and-trade regulations. The regulation applies to all owners of SF6-insulated switchgear. It imposes an annual maximum rate of SF6 emissions that is reduced by 1 percent over a ten-year period from 2011 to 2020. From 2020 onwards, the maximum emission rate is not to exceed 1 percent. CARB is also proposing regulatory amendments to phase out the use of SF6 in gas-insulated equipment (GIE) starting in 2025. The phaseout schedule limits the GIE owners’ ability to acquire new SF6 GIE without an approved SF6 phaseout exemption.
The 310 CMR 7.72 regulation aims to reduce SF6 emissions from gas-insulated switchgear. Companies and municipalities that own, lease, operate, or control gas-insulated switchgear (GIS) that contain SF6 (collectively referred by the regulation as “GIS owners”) and are located in Massachusetts are required to comply with this regulation. It imposes a maximum annual SF6 leak rate of 1 percent for GIS purchases after 2015. If the annual average leakage rate for the new GIS equipment exceeds 1 percent, the GIS owner must describe the actions that will be taken to reduce the emission rate in the future.
In Canada, the management and reduction of SF6 emissions fall under federal and provincial regulations. At the federal level, Environment and Climate Change Canada (ECCC) is responsible for developing and implementing regulations related to greenhouse gases, including SF6. Provincially, the Ministère de l'Environnement et de la Lutte contre les changements climatiques (MELCC) in Quebec has specific regulations and guidelines pertaining to the use and handling of SF6.
In 2013, Québec set up a cap-and-trade system for greenhouse gas emission allowances (C&T system) to fight climate change. Its primary objective is to encourage businesses and citizens to innovate and change their behaviour in order to reduce GHG emissions.
In 2014, Québec linked its system to California’s as part of the Western Climate Initiative, thereby creating the largest carbon market in North America and the first to be designed and managed by sub-national governments in different countries. This market expanded again with the signing of an agreement with Ontario in September 2017, making the link between the Québec, California and Ontario markets official on January 1, 2018. Despite Ontario’s withdrawal when it repealed its cap-and-trade regulation on July 3, 2018, Québec and California are continuing their collaboration.
Source: https://icapcarbonaction.com/en/ets/canada-quebec-cap-and-trade-system
Changes in SF6 regulations in the United States can indirectly impact Canada due to several factors:
Trade and Equipment Standards: The United States and Canada have close economic ties, including the import and export of electrical equipment and SF6-filled devices. Changes in US regulations may influence equipment standards and requirements, which could subsequently impact the availability and import/export of SF6 equipment in Canada.
Harmonization Efforts: Canada and the United States often collaborate on environmental regulations and strive for harmonization where feasible. If the US implements stricter regulations or adopts new guidelines for SF6 use, it may influence or serve as a reference point for potential updates or harmonization of SF6 regulations in Canada.
International Agreements: Both the United States and Canada are signatories to international agreements, such as the United Nations Framework Convention on Climate Change (UNFCCC) and the Montreal Protocol. International developments and commitments related to SF6 emissions reduction can influence regulatory actions in both countries.
Best Practices and Information Sharing: Regulatory changes in the United States often prompt discussions and information sharing among industry stakeholders, regulatory agencies, and professional organizations. This exchange of knowledge and best practices can inform decision-making processes and potentially influence SF6 regulations in Canada.
Industry changes
The regulatory changes in the industry have companies looking for alternatives, seeking out solutions that will stand the test of time and are sustainable and environmentally friendly. One direction points to the use of equipment that does not utilize SF6, such as vacuum circuit breakers.
Vacuum circuit breakers offer several advantages compared to other types of circuit breakers:
High Dielectric Strength: The latest technologies in vacuum interrupters provide excellent dielectric strength, allowing them to withstand high voltages and provide reliable insulation.
Maintenance-Free Operation: Vacuum circuit breakers are typically maintenance-free, as they do not require regular inspection of gas, or lubrication like some other types of circuit breakers.
Fast Switching Speed: Vacuum interrupters have a fast switching time, enabling quick and efficient interruption of electrical current. This feature is particularly useful in applications where rapid circuit interruption is essential, such as in fault protection or switching operations.
Economical Operation: Vacuum technologies don’t require expensive equipment for managing gas such as arc by-product analyzers, gas monitors, disposal plans, management programs for gas, etc. The common tool with gas breakers is the moisture meter.
Find out more about Vacuum circuit breakers here:
Environmental Friendliness: SF6 gas, commonly used in other types of circuit breakers, has a high global warming potential (GWP). Vacuum circuit breakers, on the other hand, are free from SF6 gas, making them environmentally friendly and contributing to greenhouse gas reduction efforts.
Long Operational Life: Vacuum interrupters have a long operational life, with a typical lifespan of several decades. This durability contributes to their reliability and reduces the need for frequent replacements.
High Breaking Capacity: Vacuum circuit breakers can handle high fault currents and have a high breaking capacity, making them suitable for applications with demanding electrical conditions.
Total Ownership Cost (TOC): TOC of vacuum circuit breakers is 40 to 60% less than that of gas circuit breakers.
While CARB is proposing regulatory amendments to phase out the use of SF6 in gas-insulated equipment (GIE) starting in 2025, it will also allow the operation of any existing equipment. This raises the need for better SF6 analyzers and SF6 handling equipment for the aging infrastructure.
DILO, which stands for "Dichtung, Isolierung, Lötfrei, Ohne Leckage" in German (meaning "Sealing, Insulation, Soldering, Leak-free"), is a company that specializes in the production of high-quality SF6 gas handling equipment and services.
DILO's zero-emission policy refers to its dedication to minimizing and ultimately eliminating SF6 gas emissions throughout its entire life cycle. This policy encompasses several key aspects:
SF6 Gas Recovery and Recycling: DILO provides equipment and services for the efficient recovery and recycling of SF6 gas from electrical equipment. This ensures that the gas is properly handled and reused, reducing the need for new SF6 gas production and minimizing emissions.
Leak Detection and Repair: DILO offers advanced leak detection systems and techniques to identify and locate SF6 gas leaks in electrical equipment. By promptly repairing any leaks, they prevent the release of SF6 into the atmosphere.
Read more about the 3Rs of SF6 handling in our article:
Read more about emission rates of SF6 gas in our article:
Find out more about DILO’s products and their ZERO Emission policy:
Gas Handling and Management: DILO emphasizes proper gas handling procedures to minimize emissions during equipment installation, maintenance, and dismantling. They provide training and support to ensure that personnel are knowledgeable and follow best practices.
SF6 Alternatives: DILO actively promotes the use of alternative gases with lower GWP as substitutes for SF6 in various applications. They provide solutions and support for the transition to environmentally friendly alternatives, contributing to the reduction of greenhouse gas emissions.
By implementing their zero-emission policy, DILO aims to help their customers and the industry as a whole achieve sustainable and environmentally responsible SF6 gas handling practices.
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Sources:https://dilo.com/blog/article/is-sulfur-hexafluoride-a-greenhouse-gashttps://www.epa.gov/eps-partnership/state-and-regional-regulations-related-sf6-emissions-electric-transmission-andhttps://ww2.arb.ca.gov/our-work/programs/elec-tanddhttps://www.mass.gov/service-details/reducing-sulfur-hexafluoride-sf6-emissions-from-gas-insulated-switchgear-310-cmr-772#:~:text=Companies%20and%20municipalities%20that%20own%2C%20lease%2C%20operate%2C%20or,requirements.%20For%20GIS%20purchased%20after%20January%201%2C%202015%3Ahttps://www.environnement.gouv.qc.ca/changementsclimatiques/marche-carbone_en.asphttps://icapcarbonaction.com/en/ets/canada-quebec-cap-and-trade-system